MAPS.ME - Fast, detailed and completely offline maps for mobile devices
SW Maps - SW Maps app enables users to record points, lines, polygons, and images to view them on the desired type of map.
OsmAnd - Global mobile map viewing and navigation for online and offline OSM maps
GPS Coordinates - GPS Coordinates is an app by Financept that comes up with features to help you in getting the GPS coordinates of your current location.
Wikiloc Outdoor Navigation GPS - Follow millions of outdoor trails and record your own GPS tracks from your smartphone.
HERE WeGo - HERE WeGo - Maps - Routes - Directions - All ways from A to B in one